Income Segregation Maps

Income Segregation in the United States’ Largest Metropolitan Areas

The disappearance of middle class neighborhoods

Over the past forty years, income inequality in the United States
has grown rapidly. The top 1% of earners earned 21% of all income in the United States
in 2012, two and a half times the 8.4% share they earned in 1970. A family at the 90th
percentile of the income distribution now earns almost 10 times as much as a family at
the 10th percentile of the income distribution; in 1970 the same families’ incomes would
have differed by a factor of 6.

One consequence of this rising income inequality has been a similarly sharp
increase in residential income segregation. As the chart below illustrates, in 1970, two-thirds
of American families in large metropolitan areas lived in middle-income neighborhoods—neighborhoods
with median incomes between 80% and 125% of the median income in their metropolitan area. By 2007,
that number had declined by a third: only 43% of families lived in such neighborhoods. Instead, a
growing number of families now live in neighborhoods that are either very poor or very affluent.
Middle-class neighborhoods, like the middle class, are rapidly disappearing.

Segregation Patterns and Trends in Specific Metropolitan Areas

This website provides a look at the patterns and trends in residential income
segregation over the past forty years in the two dozen most populated metropolitan areas of the
United States. We focus here on the segregation of families because segregation may be particularly
consequential for children. Children are less mobile than adults, so where they live may play a much
larger role in shaping their experiences, friendships, social interactions, and educational
opportunities than it may for adults.

Use the map or the dropdown menu below to navigate to different
metropolitan areas and explore how segregation patterns have changed over time in any of these places.

Data Sources and Calculations

The data here are from the 1970, 1980, 1990, and 2000 U.S. Census and the 2005-09 American Community
Survey (we refer to the 2005-09 period as “2007” for simplicity here). The Census and American Community
Survey provide information on the distribution of family income in each census tract (a census tract is a
neighborhood with a population of roughly 4,000 people).

For each year, we calculated the median income of families in each of the largest metropolitan areas,
and the median income of families in each census tract in those metropolitan areas. We then computed,
for each of these census tracts, the ratio (r) of the tract’s median family income to that of
its metropolitan area. Based on this ratio, we classified each tract as affluent (r≥1.50);
high-income (1.25≤r<1.50); high middle-income (1.00≤r<1.25); low middle-income (0.80≤r<1.00);
low-income (0.67≤r<0.80); or poor (r<0.67). An affluent neighborhood, therefore, is one where
more than half of the families have incomes at least one-and-a-half times greater than the median
income in their metropolitan area. Likewise, a poor neighborhood is one where more than half of the
families have incomes less than two-thirds of the median income in their metropolitan area.
These definitions make it possible to compare neighborhood income levels over time, even as the
income distribution in metropolitan areas changes. They also allow us to compare patterns across
metropolitan areas, despite differences in their local income distribution and cost-of-living.

In 1970 and 1980, not all areas of the United States were divided into census tracts.
On the maps on the following pages, these “non-tracted areas” are shown in white, indicating we
have no income data for those places. Generally, only sparsely-populated semi-rural regions on
the periphery of metropolitan areas were non-tracted in 1970 and 1980; the absence of data for
these places has little effect on the calculation of segregation trends.

Further Reading and Resources

For more information on income segregation patterns, trends, and causes, and
for more detail on the data and methods used to produce the figures on this site, please see: